Signaling system



Oct. 30, 1928. v 1,689,835 L. ,R. KRUMM I SIGNALING SYSTEM Filed Nov. 1921 INVENTOR WITNESSE /Q M zw/m? 477mm Patented (Jet. 30, 1928.-

UNITED STATES,

PATENT. OFFICE.

hours a. KRUMM, or New YORK, N. Y.

SIGNALING SYSTEM.

Application "filed November2, 1921.' Serial No. 512,197;

ceiving stations unable to receive undamped l wave signals.

As is wellknown, the. energy radiated by damped-wave systems consists of discontinuous groups of damped oscillatory wave trains of an audible group frequency. The effect of each wave t-rai-n,upon wave responsive apparatus, is to cause a single click in a tele-' phone receiving device associated therewith. By reason of the fact that a signal, that is,

a dot or a dash, is composed of a number of such impulses, their combined effect isto cause an audible note in the telephonereceiving device. The periodicity of the note may be varied by controlling the group frequency at the transmitting station. Receiving systems, which are only responsiveto damped wave trains, will hereinafter be referred to as damped receiving systems. I a

The energy, however, which is radiated by undamped systems, such, for example, as arcconverter systems, is distinguished from that radiated by dampedtransmitters in. that the waves are of uniform intensity during the signaling periods. A signal, therefore, correspondingto a dot or a dash, comprises an unmodulated, undamped wave train. which merely causes a click at the beginning and at the end of the signal in the telephone receivers of a damped receiving system.

An undamped wave, in order to be received, must be periodically modulated at an audiblefrequency. The modulation may be accomplished by any means known to the art, such, for example, as by heterodyning the received impulses with locally generated currents of a slightly different frequency. Receiving systems which are provided with means for periodically modulating the received impulses will hereinafter be referred to as undamped receiving systems.

According to my invention, I provide Ill) - work.

which means whereby the undamped oscillations in sustained-current transmitting systems may be periodically modulated to permit their reception bydamp'ed receiving systems.

Briefly speaking, the desired result may be accomplished either by controlling the potential drop across an arc,.or by selectively and periodically rendering an absorbing circuit effective or non-effective. My invention is particularly adapted for marine service where the inability of undamped transmitting stations to communicate with damped receiving stat-ions has heretofore required an additional spark-transmitter for emergency My invention may best be understood by reference to the accompanying drawings, in

Figure 1 isa diagrammatic view of circuits and apparatus embodying my'invention.

Fig. 2 is a similar view showing a'modification of the means for controlling the oscillations in the antenna circuit. 1 I

.Fig. 3 is a similar view showing still an other modification whereby the oscillations in the antenna circuit may be selectively controlled.

Referring to Fig. 1, an are 1 is energized by means'of a direct-current source of energy through reactance coils 3', a resistor 4, and blow-out coilsf). An antenna circuit, which is energizedby the are 1, comprises an antenna 6, a variable inductance coil 7., the are 1, a coupling coil 8 and a ground lead 9.

An absorbing circuit, which is operatively coupled to the antenna circuit, comprises a coupling coil 10, a co ndenser'll and an energy absorbing element or resistor 12. The r sist ance of resistor 12 is substantially equal to the total antenna'resistance. The condenser 11, which is included in the absorbing circuit, is shunted by a circuit whichincludes a rotray-spark gap orother commutating device 13, and a key 14. and which may include also a resistor 15. lVhile I have shown the are 1- directly connected in the antenna circuit, my invention is not to be limted thereby,-but is equallyapplicable to systems wherein the arc is inductively coupled tot-he antenna circuit In operation, upon the energization of the are 1, high-frequency Oscillations are caused the antenna circuit. In the systems therein shown,'the modulation is efi'ected by selectively and periodically varying the potentialdrop across the are 1 and the intensity of the transverse magnetic fields of the blow-out coils 16 and 17. V

Referring more specifically to Fig. 2, the absorption circuit of Fig. 1 is replaced by a circuit which'is shunted around the arc. The

circuit 'just mentioned exten'dsbetweenthe direct-current V supply conductors 18 and 19 and comprises the pair of auxiliary-field coils 16 and 17 a key 19 and a rotating commutator device 20; V

The auxiliary field coils 16 and 17 may be either compound or differentially wound with respect to the blowout coils 5, in order that the variations in the intensity of the magnetic field may causev corresponding variations in the stability of the are. A resistor 21 is em ployed to limit the passage of currents in the supply circuit during that period in which the potential across the arc is lowered by the closing of the shunt through the auxiliary coils 16 and 17. v V g In operation, with the key 19closed, the efliciency of the are is periodically varied at an audible rate, thereby causing the passage ofmodulated currents in the antenna circuit. As 1n the previous figure, the radiation of the modulated energy may be selectively coni trolled by means of the key 19.

Referring to Fig. 3, the arrangement shown differs from that of Fig. 2 in the provision of means whereby an audio-frequency component of energy may be impressed upon the are 1 to cause corresponding changes in the are efiiciency.

Briefl' speaking, the desired result is accomplis ed by shunting the blow-out coils 5 with an auxiliary circuit which includes a condenser-'22 and a key 23. The capacity of the condenser is tunedto the inductance of the blow-out coils 5' to constitute an audio-frev queney circuit, comprising the are 1, the blowout coils 5, the condenser 22 and the key 23.

In operation, when the key 23 is closed, the

v auxiliary circuit oscillates at an audible frequency to periodically vary the drop in potential across thearc 1. Theeiiect of'the varying potential-drop across the arc isto cause corresponding.modulations in the entransmission of signals capable'of ergy in the antenna circuit, As in the systems of the previous figures, the radiation oi the modulated energy is selectively controlled by means of the key 23. r

.t will be noted. that, when the key 23 is open, the system operates as an undampedwave transmitter. If desired, the apparatus maybe operated altogether as an undamped wave transmitter with the key. 23 open, and

signals may be formed by any of the Well known systems of control, such, for example, as by means of a key (not shown) for shunting a portion of the antenna inductance 7.

The particular advantage of my invention is the provision of improved means whereby an undamped transmission system may be readily modified to. permit the transmission elimination of the'sparlcgap set Which, heretotore, has been essential for the eificient damped receiving systems;

WVhile I have shown three embodiments of my invention, it is capable of various other changes and modifications without departing from the spirit of my invention. .I desire, therefore, that only such limitations shall be imposed thereon as are indicated in the appended claims. Y

I'claim as my invention:

7, 1. In" a wireless transmission system, an are, a supply circuit for energizing said are, 7

means for causing saidarc to oscillate, said supply. circuit including blo w out coils for producing a transverse magnetic field across said are, anda condenser shunted around said blow-"out coils, thecircuit including said condenser and blow-out coils being tuned to an audible frequency, whereby oscillating curof signals therefrom capable of affecting rents having an audible group-frequency may be established in said are.

2. In a wireless transmission system, an

arc, a supply circuit for energizing said arc, means for causing said are to oscillate, said supply circuit including blow-out coils for producing a transverse magnetic field across said arc, and a circuit including a condenser and akey shunted around said are and said blow-out coils, wherebythe etficiency of said are may be varied at a predetermined fre quency determined by the tuning of said condenser.

3. In an arc transmitter, a source of current,

an arc energized therefrom, means including blow out'magnets ior causing said are to generate high-frequency osclllations and means, energized by energy diverted from said blowout magnets, for impressing a low-frequency magnets, for impressing a low-frequency modulation on said oscillations. modulation on said oscillations, and signaling 4:. In an arc transmitter, a source of current, means for controlling said modulating means. 10 an arc energized therefrom, means including In testimony whereof, I have hereunto subbloW-out magnets for causing said are to genscribed my name this 28th day of October, crate high-frequency oscillations, means, en- 1921. ergized by energy diverted from said blow-out LOUIS R. KRUMM. 

